In late 1987, Hagi transferred to Steaua București as the team prepared for their European Super Cup final against Dynamo Kyiv. The original contract was for one game only, the final. However, after winning the trophy, where Hagi scored the only goal of the match, Steaua did not want to release him back to Sportul Studențesc and retained him. During his Steaua years (1987–1990), Hagi played 97 Liga I games, scoring 76 goals. He and the team reached the European Cup semi-final in 1988 and the final in the following year, while Hagi finished as one of the competition's top scorers in the former edition of the tournament. Hagi and Steaua were the champions of Romania in 1987, 1988 and 1989 and as well as winning the Cupa României in 1987, 1988 and 1989. His strong performances had him linked with Arrigo Sacchi's Milan and Bayern Munich, but Nicolae Ceaușescu's communist government rejected any offer.

After two years at Barça, Hagi signed for Turkish club Galatasaray. At Galatasaray, he was both successful and highly popular among the Turkish supporters. Hagi was an important member of a team that would win four consecutive league titles. In 2000, at age 35, Hagi had the best days of his career winning every possible trophy with Galatasaray. Gala won the 1999–2000 UEFA Cup after defeating Arsenal in the final, a match in which Hagi was sent off for punching Arsenal captain Tony Adams.[10] This was followed by the capture of the UEFA Super Cup with a historic win against Hagi's former club Real Madrid. Both feats were firsts, and remain unmatched in Turkish football history. The mass hysteria caused by these wins in Istanbul raised Hagi's popularity even further with the fans and prompted French ex-internationalLuis Fernández to say, "Hagi is like wine, the older it gets, the better he is."

When he retired in 2001, Hagi remained one of the most beloved players in the Turkish and Romanian championships. Hagi is highly praised by the Galatasaray supporters. The classic chant "I Love You Hagi" was adopted by Gala fans since his arrival at Galatasaray.